PROJECT SUMMARY The unifying hypothesis to be tested in this proposal is that the mutant CFTR correcting and potentiating roles of guanylate cyclase 2C (GC-C)-agonists can restore fluid homeostasis of the gut in a subset of population with chronic constipation emanating from mutant CFTR functional deficit. We will test this hypothesis using patient derived intestinal stem cells derived from crypts (enteroids) to study fluid secretion in vitro; and the induced pluripotent stem cells (iPSCs) derived human intestinal organoids (HIOs) in mouse kidney capsule and be used as models to study fluid secretion in vivo. The proposed studies are highly significant because (i) it addresses the pathologies of several deadly human diseases by utilizing models from humans; (ii) it has clinical relevance and implications; (iii) it is a multidisciplinary project covers basic biomedical studies, assay developments, and drug discovery using personalized human stem cell cultures.